Forward Genetic Screening Identifies a Small Molecule That Blocks Toxoplasma gondii Growth by Inhibiting Both Host- and Parasite-Encoded Kinases

PLoS Pathogens

Graham B. Wiley¹  Patrick M. Gaffney¹  Marc Jan Gubbels²  Andrew Farrell²  Gabor Marth²  Aaron McLain³  Ashley Dittmar³  Kevin M. Brown⁴  Ira J. Blader⁴  Elena Suvorova⁵  Michael White⁵ 

[1] Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America;Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America;Department of Microbiology and Immunology, University at Buffalo, Buffalo, New York, United States of America;Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America;Departments of Molecular Medicine & Global Health, University of South Florida, Tampa, Florida, United States of America

关键词: Parasite replication;    Parasitic diseases;    Toxoplasma;    Kinase inhibitors;    Tachyzoites;    Host cells;    Parasitic cell cycles;    Vacuoles;   

DOI  :  10.1371/journal.ppat.1004180

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The simultaneous targeting of host and pathogen processes represents an untapped approach for the treatment of intracellular infections. Hypoxia-inducible factor-1 (HIF-1) is a host cell transcription factor that is activated by and required for the growth of the intracellular protozoan parasite Toxoplasma gondii at physiological oxygen levels. Parasite activation of HIF-1 is blocked by inhibiting the family of closely related Activin-Like Kinase (ALK) host cell receptors ALK4, ALK5, and ALK7, which was determined in part by use of an ALK4,5,7 inhibitor named SB505124. Besides inhibiting HIF-1 activation, SB505124 also potently blocks parasite replication under normoxic conditions. To determine whether SB505124 inhibition of parasite growth was exclusively due to inhibition of ALK4,5,7 or because the drug inhibited a second kinase, SB505124-resistant parasites were isolated by chemical mutagenesis. Whole-genome sequencing of these mutants revealed mutations in the Toxoplasma MAP kinase, TgMAPK1. Allelic replacement of mutant TgMAPK1 alleles into wild-type parasites was sufficient to confer SB505124 resistance. SB505124 independently impacts TgMAPK1 and ALK4,5,7 signaling since drug resistant parasites could not activate HIF-1 in the presence of SB505124 or grow in HIF-1 deficient cells. In addition, TgMAPK1 kinase activity is inhibited by SB505124. Finally, mice treated with SB505124 had significantly lower tissue burdens following Toxoplasma infection. These data therefore identify SB505124 as a novel small molecule inhibitor that acts by inhibiting two distinct targets, host HIF-1 and TgMAPK1.

【 授权许可】

CC BY